Mat switch

ABSTRACT

A flexible casing of electrical insulating material, having spaced top and bottom walls and a peripheral wall enclosing a pair of spaced apart electrical conductor plates. An elongated spacer strip of flexible resilient electrical conducting material is disposed between the conductor plates, the strip being secured along a longitudinally extended transversely central portion to one of the conductor plates, but insulated therefrom, by a band of insulating material. The strip includes a pair of longitudinally extending flanges at opposite edges of the strip, the flanges diverging toward the opposite conductor plate, the outer edge portions of the flanges engaging the other conductor plate. Downward movement of the top wall and top conductor plate bends one or more of the flanges, so that the flanges engage both conductor plates to close an electrical circuit.

UnitedijSta teSjPaten 1 Steinback I it July 23, 1974 MAT SWITCH [75]Inventor: Clarence I. Steinbeck, Edina, Minn.

[73] Assignee: Acrometal Products, Inc., Minneapolis, Minn.

221 Filed: Aug. 16,1973

211 App]. No.:'388,993

52 11.5. C1. 200/86.n,-340'/272 s1 lnt.Cl. H01hl3/l6 58 Field of Search200/86 R, 85 R; 340/272 [56] I References Cited I UNITED STATES PATENTS;2,813,163 11/1957 Durbin .200/86 R 2,813,164 11/1957 Durbini. 200/86 RPrimary ExaminerDavidl Sm ith, Jr. Attorney, Agent, or Firm'Merchant,Gould, Smith &

Edell I t [57] ABSTRACT A flexible casing of electrical insulatingmaterial, having spaced top and bottom walls and a peripheral wallenclosing a pair of spaced apart electrical conductor plates. Anelongated spacer strip of flexible resilient electrical conductingmaterial is disposed between the conductor plates, the strip beingsecured along a longitudinally extended transversely central portion toone of the conductor plates, but insulated therefrom,

by a band of insulating material. The strip includes a pair oflongitudinally extending flanges at oppositeedges of the strip, theflanges diverging toward the opposite conductor plate, the outer edgeportions of the flanges engaging the other conductor plate. Downwardmovement of the topwall and top conductor plate bends one or more of theflanges, so that the flanges engage both conductor plates to close anelectrical circuit. I

, 6 Claims, 4 Drawing Figures MAT swrrcu BACKGROUND OF'TI-IE INVENTIONcontrolling door operating mechanisms.

j Many attempts have been made heretofore to provide a pressure operatedstrip or mat switch which will withstand heavy 'usage,'extremes intemperature conditions and entry of moisture and other foreign materialwith varying degree of success; Some have been costly to produce andothers haveexperienced early failure due to one or more of theabove-mentioned causes.

SUMMARY or THE INVENTION 1 An important object of this invention is theprovision of a switch which is relatively'simple and inexpensive toproduce and which is highly efficient in operation.

Another object of this invention is the provision of a switch whichisrugged in construction, long-wearing in use, and imperviousjtovarying. weather and environmental conditions. I

To the above endsfl provide a mat switch which comprises a casing ofrubber-like insulating material and having a bottom wall, a flexible topwall upwardly spaced'from thebottom wall, and a peripheral wall joiningthe top and bottom walls at their marginal edges. A pair of verticallyspaced upper and lower conallel relationship between the conductorplates laterally inwardly of the peripheral wall of the casing. Eachconnector strip hasfan elongated transversely intermediate portion thatismounted on one of the conductor plates by a band of electricalinsulating material disposed between the intermediate portion and theone conductor plate; the condu'ctor'strip being formed at the oppositeedges of the intermediate portion to provide longitudi-- nally extendingflanges that diverge toward the opposite conductor plate. Each of theflanges has an outer FIG. 2 is an enlarged fragmentary section taken onthe line2-2 of FIG. 1;

FIG. 3 is a view corresponding to FIG. 2 but showing a switch closedposition of some of theparts; and 1 FIG. 4 is a still further enlargedfragmentary section corresponding generally to a portion of FIG. 2,showing electrical conductors connected to the conductor plates of thisinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In the embodiment ofthe invention illustrated, a mat, indicated generally at 1, is shown ascomprising a bottom wall 2, a top wall 3, and a peripheral wall 4joining the bottom and top walls 2 and 3 at their marginal edgesanddisposing the top wall 3 in overlyingspaced generally parallelrelationship to the bottom wall 2. Although the mat 1 may be of anydesired outline, it may be assumed that the same is generallyrectangular for the purpose of the present example. Preferably, the matl is made from flexible electrical insulating material, such "as rubberor synthetic plastic material having electrical insulating qualities,the top, bottom and peripheral walls being bonded-together provide aunitary wall structure'and to seal the interior of the mat against entryof foreign vmaterial. Upper and lower conductor plates Sand 6respectively are disposed in face-to-face engagement with the innersurfaces of the top wall3 and bottom wall 2 respectively and aremaintained in spaced apart relationship at their marginal edge portionsbya'marginal spacer strip 7 of suitable electrical insulating material.Preferably, the conductor plates 5 and 6 are of relatively thinflexible'sheet metal such as copper, bronze or other metal having goodelectrical conductivity. As shown fragmentarily in FIG. 4, conductorwires 8 and 9 are suitably secured to the conductor plates 5 and 6respectively, and may be assumed to extend outwardly of the mat 1 toother portions of a control circuit for whatever mechanism is to becontrolled by the switch of this invention. It will be appreciated thatthe conductors 8 and 9 are covered with 7 suitable insulationoutwardly'of their connection to their. respective conductor plates,,andthat a sealed edge portion that engages the opposite conductor plate ,toyieldingly hold. the conductor plates in spaced apart relationship. Theouter edge. portion of each flange. is preferably of double stripmaterial'thickness, being formed by folding the outer edge portions ofthe strip backwardly "uponthemselves. When downward movenient isimparted to the top casing wall, at least one of the flanges is bentsothat it engages both the upper and lower conductor plates and closes acircuit through the plates;

DESCRIPTION OF THE DRAWINGS FIG. 1 is a'fragmentary view in perspectiveof a mat switch produced,in accordance with this invention, away andsome parts being some parts, being broken shown in section.

connection, not shown, therebetween and the mat wall structure iseffected in theusual manner so as to seal the interior of the mat 1against entry of foreign matter into the mat at the points where theconductors 8 and between the conductor plates 5 and 6 when predetermineddownward movement is imparted to the top wall 3, I provide a pluralityof elongated switch members indicated generally at' 10 disposed inlaterally spaced parallel relationship laterally inwardly of themarginal spacer strip 7. The switch members 10 are substantiallyidentical in structure, eachthereof including an' elongated strip offlexible resilient electrical conductor material such as bronze or othermetal having similar characteristics, each strip being indicatedgenerally at 11.

The outer longitudinal edges of the flanges 13 are bent or foldedbackwardly into overlying engagement with the flanges 13, as indicatedat 14, to provide longitudinal edge portions 15 that engage the topsurface of the lower conductor plate 6. Each of the connector strips llis secured to the under surface of the conductor plate by means of arespective one of aplurality of bands 16 of insulating material that aresuitably bondedor adhered to the upper conductor plate 5 and 'to theintermediate portion 12 of each connector strip When downwardmovement'is imparted to the upper conductor plate 5, such as would becaused by a person stepping upon an overlying portion of the top matwall 3, an underlying portion of one or more of the flanges 13 will bendor flex to the extent that the back-folded portion 14 of the flange 13will make contact with the upper conductor plate 5, while the edgeportion 15 continues to engage the lower conductor plate 6, whereby toestablish an electrical connection between the conductor'plates 5 and 6,as shown in FIG. 3. Then, as soon as weight of a person or other givenobject is removed from the top wall 3 of the mat l, the resilience ofthe flexed flange 13 will cause the same to assume its normal shapeshown in FIGS. 2 and 4 to break the connection between the conductorplates 5 and 6.

Should downward pressure be applied to an' area intermediate a pair ofswitch members 10, the upper conductor plate-5 will flex sufficiently tomake contact directly with the lower conductor plate 6. At the sametime, depending upon the area over which downward pressure is applied,one or more of the adjacent flanges 13 will also flex to a point whereinthe circuit is closed between the plates 5 and 6 either directly or bymeans of a switch member. 10 or both. The resilience of the plate 5, aswell as that of the adjacent switch member or members 10, will cause theupper plate 5 to move upwardly out of engagement with the lowerconductor plate 6 as soon as downward pressure against the upperconductor plate is removed.

While I have shown and described a mat having a plurality of connectorstrips 11 therein, it will be understood that mats can be made havingvarious shapes and dimensions and that this invention contemplates a matof-suchwidth as to require but a single switch member 10. Such a switchconstruction is particularly adapted for operation by vehicles runningthereover, to control various types of electrical circuits such as forcounting devices, parking token dispensing apparatus, and others.

By providing switch members having the construction disclosed, the matswitch of this invention may be subject to loads highly in excess ofnormal loads without causing the material of the switch members to bebent beyond its elastic limit, whereby the active life of the mat switchof this invenion is substantially greater in overlying spaced generallyparallel relationship to said bottom wall, and a peripheral wall joiningsaid top and bottom walls at their marginal edges, said top and bottomwalls having opposed inner surfaces in spaced apart relationship;

b. vertically spaced upper and lower conductor plates disposed inface-to-face engagement with the opposed inner surfaces of said top andbottom walls respectively;

c. and spacer means between said conductor plates inwardly spaced fromsaid peripheral wall and including:

1. an elongated connector strip of flexible resilient electricalconductor material formed to provide a generally flat transverselyintermediate portion and a pair of longitudinal flanges disposed atoblique angles to said intermediate portion,

2. a band of electrical insulating material interposed between saidintermediate strip portion and one of said conductor plates and adheredto said strip portion and said one of the conductor plates to insulatesaid strip portion from said one of the conductor plates,

3. said flanges diverging toward the other of said conductor plates andhaving outer longitudinal edge portions in engagement with said otherconductor plate to yieldingly hold said conductor plates in spaced apartrelationship,

4. said strip being bent responsive to predetermined downward movementapplied to said top wall and upper conductor plate to move at least oneof said flanges into electrical conducting engagement with both of saidconductor plates.

2. The mat switch defined in claim 1 in which said flanges have portionsfolded backwardly upon themselves on longitudinal lines to provide saidouter edge portions with a double material thickness.

3. The mat switch defined in claim 1 in which said band of insulatingmaterial is secured to said upper conductor plate, said flangesdiverging downwardly from said band, said outer longitudinal edgeportions of the flanges engaging said lower conductor plate.

4. Themat switch defined in claim 3 in which said band of insulatingmaterial has a thickness at least equal to that of the material of saidstrip, said flanges having portions folded backwardly into overlyingengagement with their respective flanges to provide said outerlongitudinal edge portions with a double thickness.

5. The mat switch defined in claim 1 in which said spacer means includesa plurality of said elongated strips of flexible resilient electricalconductor material disposed in laterally spaced parallel relationship,and a plurality of said bands of electrical insulating material one foreach of said strips, said bands being secured to said upper conductorplate, the flanges of each strip diverging downwardly toward said lowerconductor plate.

6. The mat switch defined in claim 5 in which each of said bands ofinsulating material has a thickness at least equal to that of thematerial of its respective strip, said flanges having portions foldedbackwardly into overlying engagement with their respective flanges toprovide said outer longitudinal edge portions with a double thickness.

1. A mat switch comprising: a. a casing of electrical insulatingmaterial and including a bottom wall, a flexible top wall disposed inoverlying spaced generally parallel relationship to said bottom wall,and a peripheral wall joining said top and bottom walls at theirmarginal edges, said top and bottom walls having opposed inner surfacesin spaced apart relationship; b. vertically spaced upper and lowerconductor plates disposed in face-to-face engagement with the opposedinner surfaces of said top and bottom walls respectively; c. and spacermeans between said conductor plates inwardly spaced from said peripheralwall and including:
 1. an elongated connector strip of flexibleresilient electrical conductor material formed to provide a generallyflat transversely intermediate portion and a pair of longitudinalflanges disposed at oblique angles to said intermediate portion,
 2. aband of electrical insulating material interpOsed between saidintermediate strip portion and one of said conductor plates and adheredto said strip portion and said one of the conductor plates to insulatesaid strip portion from said one of the conductor plates,
 3. saidflanges diverging toward the other of said conductor plates and havingouter longitudinal edge portions in engagement with said other conductorplate to yieldingly hold said conductor plates in spaced apartrelationship,
 4. said strip being bent responsive to predetermineddownward movement applied to said top wall and upper conductor plate tomove at least one of said flanges into electrical conducting engagementwith both of said conductor plates.
 2. The mat switch defined in claim 1in which said flanges have portions folded backwardly upon themselves onlongitudinal lines to provide said outer edge portions with a doublematerial thickness.
 2. a band of electrical insulating materialinterpOsed between said intermediate strip portion and one of saidconductor plates and adhered to said strip portion and said one of theconductor plates to insulate said strip portion from said one of theconductor plates,
 3. said flanges diverging toward the other of saidconductor plates and having outer longitudinal edge portions inengagement with said other conductor plate to yieldingly hold saidconductor plates in spaced apart relationship,
 3. The mat switch definedin claim 1 in which said band of insulating material is secured to saidupper conductor plate, said flanges diverging downwardly from said band,said outer longitudinal edge portions of the flanges engaging said lowerconductor plate.
 4. The mat switch defined in claim 3 in which said bandof insulating material has a thickness at least equal to that of thematerial of said strip, said flanges having portions folded backwardlyinto overlying engagement with their respective flanges to provide saidouter longitudinal edge portions with a double thickness.
 4. said stripbeing bent responsive to predetermined downward movement applied to saidtop wall and upper conductor plate to move at least one of said flangesinto electrical conducting engagement with both of said conductorplates.
 5. The mat switch defined in claim 1 in which said spacer meansincludes a plurality of said elongated strips of flexible resilientelectrical conductor material disposed in laterally spaced parallelrelationship, and a plurality of said bands of electrical insulatingmaterial one for each of said strips, said bands being secured to saidupper conductor plate, the flanges of each strip diverging downwardlytoward said lower conductor plate.
 6. The mat switch defined in claim 5in which each of said bands of insulating material has a thickness atleast equal to that of the material of its respective strip, saidflanges having portions folded backwardly into overlying engagement withtheir respective flanges to provide said outer longitudinal edgeportions with a double thickness.